Magnetorheological polishing equipment and method based on machine vision to adjust processing posture

Abstract

The present invention relates to the field of optical processing technology, and in particular to a magnetorheological polishing device and method for adjusting processing posture based on machine vision. The device comprises a robot, a control unit, a magnetorheological processing module, and a machine vision device. The magnetorheological processing module is arranged at the free end of the robot. The robot drives a polishing wheel in the magnetorheological processing module to process an optical element using magnetorheological fluid as a medium, and the machine vision device measures the ribbon thickness of the magnetorheological fluid during the processing. In the method, the real-time change of the ribbon thickness of the magnetorheological fluid during the processing is measured by the machine vision device, and the processing posture of the robot and the magnetorheological processing module is then adjusted in real time, thereby achieving real-time constant control of the removal function.

Description

Technical Field

[0001] The present invention belongs to the field of optical processing technology, and in particular relates to a magnetorheological polishing device and method for adjusting processing posture based on machine vision. Background Art

[0002] Magnetorheological finishing (MRF) is an advanced optical manufacturing technology that has been developed in recent years. It offers numerous advantages, including stable removal performance, controllable edge effects, minimal subsurface damage, no photocopying, strong shape-modifying capabilities, and high machining accuracy. Consequently, MRF has garnered widespread attention in high-precision optical processing. The hardware of existing magnetorheological polishing equipment mainly includes three parts: motion actuator, circulation system and polishing wheel module. The motion actuator is usually a CNC machine tool, but CNC machine tools have some shortcomings (such as low degree of freedom, large footprint, high cost, etc.), which limit the deviation of aspheric surfaces and make it difficult to perform precise posture control along the surface normal. The most important component in the circulation system is the supply source. Peristaltic pumps and centrifugal pumps are currently the main types of magnetorheological fluid supply sources. Peristaltic pumps will produce a pulse effect when working, which in turn affects the stability of the magnetorheological fluid in pipeline transportation, and ultimately affects the stability of the removal function. The centrifugal pump has a small pulse effect when working, and the magnetorheological fluid is more stable when transported in the pipeline, and has less impact on the change of the removal function. Therefore, it is more suitable for magnetorheological supply systems. However, there is still a major problem with using a centrifugal pump as the supply source for the magnetorheological fluid supply system: when the water outlet (nozzle) of the supply system is processed along the curved surface of the optical component, the nozzle will move up and down within the working area. When the position of the centrifugal pump is constant, the pressure between the centrifugal pump and the nozzle will change, and the originally stable magnetorheological fluid will also change. The thickness and width of the ribbon formed by the magnetorheological fluid after passing through the polishing gap will also change accordingly, resulting in a change in the removal function and affecting the final processing accuracy.

[0003] In response to these shortcomings of CNC machine tools, researchers have introduced six-degree-of-freedom industrial robots into the field of optical processing in recent years. Six-degree-of-freedom industrial robots have the advantages of high degrees of freedom, small footprint, large processing range, and low cost, which make up for the shortcomings of CNC machine tools. Therefore, when the magnetorheological polishing module is integrated into the industrial robot, it is theoretically possible to achieve high-precision processing of large-aperture complex curved optical components.

[0004] However, due to the influence of factors such as processing, assembly, load, trajectory planning and reduction ratio, the execution accuracy of the robot's free end is low, and the polishing gap changes greatly during the processing. At the same time, magnetorheological polishing technology is an optical processing technology with high certainty of the removal function. The requirements for the change of the polishing gap during the polishing process are high. Generally, the polishing gap of the magnetorheological CNC machining center changes in tens of microns (PV<0.1mm), while the trajectory accuracy of common commercial robots is generally in the sub-millimeter to millimeter range. This leads to large changes in the polishing gap during the processing. The thickness of the ribbon will change after the magnetorheological fluid passes through the polishing gap, and the certainty of the removal function is reduced, affecting the final processing accuracy. Therefore, the motion accuracy of the current commercial large-scale six-degree-of-freedom industrial robots often cannot meet the requirements of magnetorheological polishing technology for the change of the removal function during high-precision polishing.

[0005] For the flow rate change problem in the centrifugal pump supply system, the commonly used method is to add a follower device to keep the vertical distance between the centrifugal pump and the nozzle outlet unchanged. However, these methods require the additional follower device to have high motion performance to keep the vertical distance from the nozzle unchanged at all times. Some solutions even place the follower device on the Z-axis of the CNC machine tool, which undoubtedly increases the motion load and equipment cost of the motion mechanism and reduces the motion performance of the equipment. In addition, the follower device cannot strictly guarantee the constant vertical distance between the centrifugal pump and the nozzle, resulting in changes in the removal function and affecting the final processing accuracy. Summary of the Invention

[0006] In view of this, the present invention aims to provide a magnetorheological polishing device and method for adjusting the processing posture based on machine vision. The machine vision equipment measures the real-time change of the ribbon thickness of the magnetorheological fluid during the magnetorheological processing, and then performs real-time regulation of the processing posture during the processing of optical elements, thereby realizing real-time constant control of the removal function.

[0007] To achieve the above object, the technical solution created by the present invention is implemented as follows:

[0008] A magnetorheological polishing device for adjusting processing posture based on machine vision comprises a robot, a control unit, a magnetorheological processing module, and a machine vision device. The magnetorheological processing module is disposed at the free end of the robot. The robot drives a polishing wheel in the magnetorheological processing module to process an optical element using magnetorheological fluid as a medium, and during the processing, the machine vision device measures the thickness of a ribbon of the magnetorheological fluid. The control unit comprises a time calculation module for calculating the measurement time of the machine vision device and the adjustment time of the magnetorheological processing module, and adjusting the machine vision device and the magnetorheological processing module based on the measurement and adjustment times. A conversion relationship module for obtaining a first conversion relationship based on the ribbon thickness and the polishing gap of the polishing wheel, and a second conversion relationship based on the ribbon thickness and the polishing wheel position. A processing program module for obtaining a processing program based on a removal function obtained by the magnetorheological processing module and importing the processing program into the magnetorheological processing module. A real-time control module for adjusting the robot's posture based on the first conversion relationship or adjusting the polishing wheel position based on the second conversion relationship to maintain the stability of the removal function during processing of the optical element.

[0009] Furthermore, the magnetorheological processing module also includes a transmission belt, a polishing motor, a nozzle, a supply system, a magnet, a real-time adjustment device and a magnetorheological mounting frame; wherein, the magnetorheological mounting frame is arranged on the free end; the polishing wheel and the real-time adjustment device are arranged on the magnetorheological mounting frame, and the real-time adjustment device adjusts the position of the polishing wheel; the polishing motor is arranged on the magnetorheological mounting frame and is connected to the polishing wheel through a transmission belt, so that the polishing motor controls the rotation of the polishing wheel, and then the polishing wheel processes the optical element; the nozzle is arranged on the magnetorheological mounting frame along the rotation direction of the polishing wheel, and the supply system transports magnetorheological fluid to the nozzle; the magnet is arranged on the magnetorheological mounting frame, and the magnet is close to the working point of the polishing wheel, so that the magnetorheological fluid is affected by the magnetic field strength of the magnet to change the stiffness of the magnetorheological fluid.

[0010] Furthermore, the real-time adjustment device includes a displacement output motor, a lead screw, and a support and fixing frame; wherein, the support and fixing frame is arranged on a magnetorheological mounting frame, the displacement output motor is arranged on the support and fixing frame, and the displacement output motor is connected to the lead screw arranged on the support and fixing frame; the polishing wheel is connected to the nut on the lead screw, so that the lead screw drives the polishing wheel to move; the control unit sends a control signal to the displacement output motor, and when the displacement output motor drives the lead screw to rotate, the lead screw drives the polishing wheel to move.

[0011] Furthermore, the machine vision device, the robot and the displacement output motor are respectively connected to the control unit to form respective communication lines, so that the control unit receives and sends signals through the corresponding communication lines.

[0012] A magnetorheological polishing method based on robot posture control, based on the magnetorheological polishing equipment for adjusting processing posture based on machine vision provided by the present invention, comprises the following steps:

[0013] A1: Control the robot's position and posture, drive the polishing wheel to process the test optical element with different polishing gaps, and obtain the first transformation relationship in the transformation relationship module;

[0014] A2: Setting a first variable range of the polishing gap and obtaining a second variable range corresponding to the ribbon thickness according to the first conversion relationship; setting a maximum polishing gap and obtaining the corresponding maximum ribbon thickness according to the first conversion relationship;

[0015] A3: Control the time calculation module and the maximum polishing gap to adjust the machine vision equipment and magnetorheological processing module;

[0016] A4: The optical element to be processed is processed in combination with the second variable range, the maximum polishing gap, and the maximum ribbon thickness. During the processing, the real-time control module adjusts the robot's position in real time, and uses the change in the polishing gap after the adjustment as input for processing the next processing position, so that the ribbon thickness at the next processing position is within the second variable range.

[0017] Furthermore, in step A1, the polishing wheel is controlled to process the test optical element with different polishing gaps, and the ribbon thickness is measured in real time by a machine vision device, and the following is obtained in the conversion relationship module:

[0018] ;

[0019] in, Indicates the polishing gap, Indicates the thickness of the ribbon, Indicates the first conversion relationship.

[0020] Furthermore, in step A4, the polishing wheel is controlled to move to the current processing position. The current ribbon thickness measured by the machine vision device With the second variable range Compare:

[0021] If the current ribbon thickness In the second variable range If the value is within , there is no need to adjust the current posture of the robot;

[0022] If the current ribbon thickness Not in the second variable range If the robot is within the specified range, the current posture of the robot needs to be adjusted:

[0023] If the current ribbon thickness changes Greater than or equal to the maximum ribbon thickness change , represents the initial ribbon thickness, represents the maximum ribbon thickness, and the robot's posture is adjusted according to the following formula:

[0024] ;

[0025] in, Indicates the position of the free end at the current processing position; Indicates the position of the free end at the previous processing position, Indicates the maximum polishing gap, Indicates the initial polishing gap;

[0026] If the current ribbon thickness changes Less than the maximum ribbon thickness change set , according to the following formula to calculate the current polishing gap Make adjustments:

[0027] ;

[0028] in, Indicates the polishing gap at the current processing position.

[0029] A magnetorheological polishing method based on polishing wheel position control, based on the magnetorheological polishing device for adjusting processing posture based on machine vision provided by the present invention, comprises the following steps:

[0030] B1: Controlling the polishing wheel to process the test optical element with different polishing gaps, and obtaining a second conversion relationship in the conversion relationship module;

[0031] B2: Setting the third variable range of the polishing wheel position and obtaining the fourth variable range corresponding to the ribbon thickness according to the second conversion relationship; setting the maximum polishing wheel position and obtaining the corresponding maximum ribbon thickness according to the second conversion relationship;

[0032] B3: Control the time calculation module and adjust the machine vision equipment and magnetorheological processing module in combination with the maximum polishing wheel position;

[0033] B4: The optical element to be processed is processed in combination with the third variable range, the maximum polishing wheel position and the maximum ribbon thickness. During the processing, the real-time control module adjusts the polishing wheel position in real time.

[0034] Furthermore, step B1 includes the following steps:

[0035] B11: Control the polishing wheel to process the test optical element with different polishing gaps, calculate the removal function volume removal rate at each processing position, and at the same time, the machine vision device measures the ribbon thickness at each processing position in real time. In the conversion relationship module, the following is obtained:

[0036] ;

[0037] in, Represents the removal function volume removal rate and ribbon thickness The third conversion relationship between

[0038] B12: Under different polishing gaps, the polishing wheel position is changed individually, and processing is performed on the test optical element to obtain the removal function volume removal rate at each processing position, and then the following is obtained in the conversion relationship module:

[0039] ;

[0040] in, Indicates the polishing wheel position Between the removal function volume removal rate The fourth conversion relationship;

[0041] B13: According to the third conversion relationship and the fourth conversion relationship, the following formula is obtained:

[0042] ;

[0043] in, Indicates the second conversion relationship.

[0044] Furthermore, in step B4, the polishing wheel is controlled to move to the current processing position The current ribbon thickness measured by the machine vision device With the fourth variable range Compare:

[0045] If the current ribbon thickness In the fourth variable range If the current polishing wheel position is within Make adjustments;

[0046] If the current ribbon thickness Not in the fourth variable range If the current polishing wheel position is within Make adjustments:

[0047] If the current ribbon thickness Greater than or equal to the maximum ribbon thickness , the current polishing wheel position Adjust to the maximum polishing wheel position ;

[0048] If the current ribbon thickness Less than the maximum ribbon thickness , according to the following formula to calculate the current polishing wheel position Make adjustments:

[0049] .

[0050] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0051] In the magnetorheological polishing equipment and method for adjusting the processing posture based on machine vision created by the present invention, the thickness of the magnetorheological fluid ribbon during the six-dimensional processing of the magnetorheological processing module driven by the robot is measured in real time by machine vision equipment, thereby adjusting the processing posture of the magnetorheological processing module in real time, thereby realizing real-time constant control of the removal function change under multi-factor coupling during the processing of the optical element; at the same time, the acquisition of posture information does not need to rely on the actual processing process, and the posture error information of the processing equipment can be obtained during the processing trial run (in which magnetorheological fluid is not introduced and no processing effect is produced), and there is no need to place the measuring equipment at the lowest point of the polishing wheel, which will not affect the actual processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The accompanying drawings, which constitute part of the present invention, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0053] Figure 1 A schematic structural diagram of a magnetorheological polishing device for adjusting processing posture based on machine vision according to an embodiment of the present invention at one viewing angle;

[0054] Figure 2 A schematic diagram of a magnetorheological polishing device for adjusting processing posture based on machine vision according to an embodiment of the present invention from another perspective;

[0055] Figure 3 A schematic structural diagram of a magnetorheological processing module according to an embodiment of the present invention;

[0056] Figure 4 This is a structural diagram of the real-time adjustment device described in an embodiment of the present invention.

[0057] Description of reference numerals:

[0058] 1. Robot; 2. Control unit; 3. Machine vision equipment; 4. Polishing wheel; 5. Laboratory bench; 6. Optical element to be processed; 7. Test optical element; 8. Real-time adjustment device; 9. Transmission belt; 10. Polishing motor; 11. Nozzle; 12. Magnet; 13. Magnetorheological mounting bracket; 14. Support bracket; 15. Displacement output motor; 16. Lead screw; 17. Nut; 18. Guide rail; 19. Slider; 20. Connecting plate. DETAILED DESCRIPTION

[0059] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation of the present invention.

[0060] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0061] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second" and the like are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, features defined as "first", "second" and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0062] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to internal connections between two components. Those skilled in the art can understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0063] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0064] like Figures 1 to 2As shown, the magnetorheological polishing device for adjusting machining posture based on machine vision according to an embodiment of the present invention includes a robot 1, a control unit 2, a magnetorheological machining module, and a machine vision device 3. The magnetorheological machining module is disposed at the free end of the robot 1. The robot 1 drives the polishing wheel 4 in the magnetorheological machining module to process an optical element 6 or a test optical element 7 on a laboratory table 5 using magnetorheological fluid as a medium. During the processing, the ribbon thickness of the magnetorheological fluid is affected by the supply system for providing the magnetorheological fluid and the polishing gap, and the polishing gap is changed by the polishing wheel position, robot posture adjustment, etc. Therefore, it is necessary to use a machine vision device 3 mounted on one side of the experimental table 5 to measure the change in the ribbon thickness of the magnetorheological fluid in real time. In an embodiment of the present invention, the machine vision device 3 uses a binocular stereo camera of the Stereo ace model of Basler. The process of using the machine vision device 3 to measure the ribbon thickness of the magnetorheological fluid includes: the machine vision device 3 collects the ribbon contour information of the polishing wheel 4 and the magnetorheological fluid, and uses any point in the non-working area of ​​the surface of the polishing wheel 4 as a reference point. The highest point on the ribbon surface of the magnetorheological fluid is the measurement point, and the height difference between the measurement point and the reference point is the change data of the ribbon thickness.

[0065] The control unit 2 includes a time calculation module, a conversion relationship module and a real-time control module. The time calculation module is used to calculate the measurement time of the machine vision device 3 and the adjustment time of the magnetorheological processing module, and to adjust the machine vision device 3 and the magnetorheological processing module according to the measurement time and adjustment time. The conversion relationship module is used to obtain a first conversion relationship based on the thickness of the ribbon and the polishing gap of the polishing wheel 4, and to obtain a second conversion relationship based on the thickness of the ribbon and the polishing wheel position of the polishing wheel 4. In the embodiment of the present invention, the polishing wheel position is defined as the distance between the working point of the polishing wheel 4 and the optical element to be processed 6 or the test optical element 7, and the working point of the polishing wheel 4 is defined as the closest point between the polishing wheel 4 and the surface of the optical element to be processed 6 or the test optical element 7 along the surface normal direction of the optical element to be processed 6 or the test optical element 7. The processing program module is used to obtain a processing program based on the removal function obtained by the magnetorheological processing module, and import the processing program into the magnetorheological processing module. The real-time control module is used to adjust the posture of the robot 1 or the polishing wheel position of the polishing wheel 4 according to the processing program and the conversion relationship, thereby maintaining the stability of the removal function when processing the optical element 6 to be processed or the test optical element 7.

[0066] Figure 3 (a) shows a schematic structural diagram of the magnetorheological processing module from one perspective. Figure 3 (b) shows the schematic structural diagram of the magnetorheological processing module from another perspective. Figure 3As shown, the magnetorheological processing module also includes a real-time adjustment device 8, a transmission belt 9, a motor 10, a nozzle 11, a supply system, a magnet 12, and a magnetorheological mounting frame 13. The magnetorheological mounting frame 13 is fixed to the free end of the robot 1, and the polishing wheel 4 and the real-time adjustment device 8 are mounted on the magnetorheological mounting frame, and the real-time adjustment device 8 is connected to the polishing wheel 4. Specifically, the head end of the connecting plate 20 is mounted on the real-time adjustment device 8, and the polishing wheel 4 is mounted on the end of the connecting plate 20, so that the real-time adjustment device 8 adjusts the position of the polishing wheel 4, thereby changing the polishing gap of the polishing wheel 4. The polishing motor 10 is mounted on the connecting plate 20, and the output end of the polishing motor 10 passes through the connecting plate 20. The bearing of the polishing wheel 4 passes through the end of the connecting plate 20. The output end of the polishing motor 10 is connected to the bearing of the polishing wheel 4 through the transmission belt 9, so that the polishing motor 10 controls the rotation of the polishing wheel 4. The manner in which the polishing motor 10 drives the polishing wheel 4 to rotate in the embodiment of the present invention can be referred to in the invention patent application with Chinese patent publication number CN118322074A, publication date July 12, 2024, and titled "Self-rotating Polishing Module Processing System." The nozzle 11 is mounted on the magnetorheological mounting frame 13 along the direction of rotation of the polishing wheel 4. The supply system delivers magnetorheological fluid to the nozzle 11, which sprays the magnetorheological fluid toward the working point of the polishing wheel 4, thereby allowing the polishing wheel 4 to process the optical element 6 to be processed or the test optical element 7 using the magnetorheological fluid as a medium. The magnet 12 is fixed to the magnetorheological mounting frame 13 via a connecting plate 20, and the magnet 12 is close to the working point of the polishing wheel 4, so that the magnetorheological fluid is affected by the magnetic field strength of the magnet 12, thereby changing the stiffness of the magnetorheological fluid. In addition, in the embodiment of the present invention, the supply system adopts the DFLD vertical multi-stage pump of Shanghai Dongfang Pump Industry Co., Ltd.

[0067] The structure of the real-time adjustment device 8 for controlling the polishing wheel 4 is as follows: Figure 4As shown, it includes a support frame 14, a displacement output motor 15 and a lead screw 16. The lead screw 16 and a nut 17 with a ball thereon together form a ball screw. The support frame 14 is mounted on the magnetorheological mounting frame 13, and the displacement output motor 15 is mounted on the top of the support frame 14. The output end of the displacement output motor 15 is connected to the lead screw 16 mounted on the support frame 14. The polishing wheel 4 is connected to the nut 17 on the lead screw 16 through the connecting plate 20, so that the lead screw 16 drives the polishing wheel 4 to move. In the embodiment of the present invention, in order to ensure that the polishing wheel 4 can move stably along the lead screw 16, it is preferred that a guide rail 18 is installed on each side of the lead screw 16 on the support frame 14, and the two guide rails 18 are parallel to the lead screw 16. At this time, the head end of the connecting plate 20 is fixedly connected to the nut 17 on the lead screw 16 and the sliders 19 on the two guide rails 18. During the machining process, the control unit 2 sends a control signal to the displacement output motor 15. When the displacement output motor 15 drives the lead screw 16 to rotate, the lead screw 16 cooperates with the two guide rails 18 to pull the connecting plate 20, thereby driving the polishing wheel 4 to move up and down.

[0068] The robot 1, the machine vision device 3, and the displacement output motor 15 of the real-time adjustment device 8 are each connected to the control unit 2 to form their own communication circuits, enabling the control unit 2 to receive and send signals via the corresponding communication circuits. Specifically, the control unit 2 receives signals from the machine vision device 3 via the communication circuits and sends control signals to the displacement output motor 15 in the real-time adjustment device 8 via the communication circuits to change the position of the polishing wheel 4. Because the polishing wheel 4 generates a strong magnetic field around it during polishing, the communication circuits are designed to avoid such strong magnetic fields.

[0069] Based on the magnetorheological polishing equipment for adjusting processing posture based on machine vision described in the embodiment of the present invention, the embodiment of the present invention also provides a magnetorheological polishing method for adjusting processing posture based on machine vision, including a magnetorheological polishing method based on robot posture control, and a magnetorheological polishing method based on polishing wheel position control.

[0070] Specific embodiment 1: The magnetorheological polishing method based on robot posture control provided in this specific embodiment, the magnetorheological polishing device based on machine vision adjustment processing posture according to the invention, combined with Figures 1 to 4 , including the following steps:

[0071] A1: Control the position of the robot 1 to drive the polishing wheel 4 to process the test optical element 7 with different polishing gaps, and obtain the first transformation relationship in the transformation relationship module. In step A1, the magnetorheological processing module is controlled to process the test optical element 7 with different polishing gaps. The ribbon thickness is measured in real time by the machine vision device 3. The transformation relationship module obtains:

[0072] ;

[0073] in, Indicates the polishing gap, Indicates the thickness of the ribbon, In this embodiment, the magnetorheological processing module is controlled to perform fixed-point processing on the test optical element 7 at different polishing gaps for a period of time.

[0074] A2: Setting the first variable range of polishing gap , and according to the first conversion relationship Get the second variable range corresponding to the ribbon thickness ,Right now:

[0075] ;

[0076] ;

[0077] Set the maximum polishing gap , get the maximum polishing gap change for:

[0078] ;

[0079] in, Indicates the initial polishing gap;

[0080] According to the first conversion relationship Get the corresponding maximum ribbon thickness ,Right now:

[0081] ;

[0082] At this time, the maximum ribbon thickness change is :

[0083] ;

[0084] in, is the initial ribbon thickness set, Indicates the maximum ribbon thickness.

[0085] The first variable range and maximum polishing gap The configuration is adaptive according to the actual situation and is not limited in this embodiment.

[0086] A3: The control time calculation module adjusts the machine vision device 3 and the magnetorheological processing module in combination with the maximum polishing gap. Step A3 includes the following steps:

[0087] A31. Count b data points measured by the machine vision device 3 within a second and obtain the time it takes for the machine vision device 3 to measure a point. ;

[0088] ;

[0089] A32. Calculate the maximum polishing gap change The time required to control the magnetorheological processing module :

[0090] ;

[0091] in, Indicates the maximum moving speed of the magnetorheological processing module;

[0092] A33, measure the vertical distance between the measuring position of the machine vision device 3 and the working point of the polishing wheel 4 , according to the vertical distance And the time required to calculate the working point of the polishing wheel 4 based on the set number of revolutions per second n of the polishing wheel 4 :

[0093] ;

[0094] in, Indicates the radius of the polishing wheel 4;

[0095] A34, calculate the maximum speed of robot 1 Minimum moving time between two adjacent processing positions :

[0096] ;

[0097] in, Indicates the distance between two adjacent processing positions;

[0098] A35. Calculation conditions Is it true: If the condition is true, then there is no need to adjust the machine vision device 3 and the polishing wheel 4; if the condition is not true, then it is necessary to adjust the data sampling frequency of the machine vision device 3 and the number of revolutions per second n of the polishing wheel 4 to make the condition true;

[0099] A36, the measurement data between each two adjacent processing positions are processed by mean filtering and then output, and the number of mean filtered data is Needs to be satisfied .

[0100] A4: The optical element 6 to be processed is processed in combination with the second variable range, the maximum polishing gap, and the maximum ribbon thickness. During the processing, the real-time control module adjusts the position of the robot 1 in real time, and uses the change in the polishing gap after the adjustment as input for the next processing position, so that the ribbon thickness at the next processing position is within the second variable range. The adjustment process is as follows:

[0101] Control the polishing wheel 4 to move to the current processing position When the current ribbon thickness is measured by the machine vision device 3 With the second variable range Compare:

[0102] If the current ribbon thickness In the second variable range Within, that is , then there is no need to adjust the current posture of robot 1;

[0103] If the current ribbon thickness Not in the second variable range Within, that is , then the current posture of robot 1 needs to be adjusted:

[0104] If the current ribbon thickness changes Greater than or equal to the maximum ribbon thickness change ,Right now , adjust the posture of robot 1 according to the following formula:

[0105] ;

[0106] in, Indicates the position of the magnetorheological processing module driven by the free end of the robot 1 at the current processing position; Indicates the position of the magnetorheological processing module driven by the free end of the robot 1 at the previous processing position;

[0107] If the current ribbon thickness changes Less than the maximum ribbon thickness variation ,Right now , according to the following formula to calculate the current polishing gap Make adjustments:

[0108]

[0109] in, Indicates the polishing gap at the current processing position. Indicates the set initial polishing gap.

[0110] Specific embodiment 2: The magnetorheological polishing method based on polishing wheel position control provided in this specific embodiment, the magnetorheological polishing device based on machine vision adjustment processing posture according to the invention, combined with Figures 1 to 4 , including the following steps:

[0111] B1: Control the polishing wheel 4 to process the test optical element 7 with different polishing gaps, and obtain a second conversion relationship in the conversion relationship module. Step B1 includes the following steps:

[0112] B11: Control the polishing wheel 4 to process the test optical element 7 with different polishing gaps, calculate the removal function volume removal rate at each processing position, and at the same time, the machine vision device 3 measures the ribbon thickness at each processing position in real time. In the conversion relationship module, the following is obtained:

[0113] ;

[0114] in, Represents the removal function volume removal rate and ribbon thickness In this specific embodiment, specifically, the polishing wheel 4 is controlled to perform fixed-point processing on the test optical element 7 for a period of time with different polishing gaps;

[0115] B12: Under different polishing gaps, the polishing wheel position is changed individually, and processing is performed on the test optical element 7 to obtain the removal function volume removal rate at each processing position, and then the following is obtained in the conversion relationship module:

[0116] ;

[0117] in, Indicates the polishing wheel position Between the removal function volume removal rate In this specific embodiment, specifically for controlling the polishing wheel 4 at different polishing gaps, individually changing the polishing wheel position, performing fixed-point processing on the test optical element 7 for a period of time;

[0118] B13: According to the third conversion relationship and the fourth conversion relationship, the following formula is obtained:

[0119] ;

[0120] in, Indicates the second conversion relationship.

[0121] B2: Set the third variable range of the polishing wheel position , and according to the second conversion relationship Get the fourth variable range corresponding to the ribbon thickness ,Right now:

[0122] ;

[0123] ;

[0124] Setting the maximum polishing wheel position , and according to the second conversion relationship Get the corresponding maximum ribbon thickness ,Right now:

[0125] .

[0126] The third variable range and maximum polishing wheel position The configuration is adaptive according to the actual situation and is not limited in this embodiment.

[0127] B3: The control time calculation module adjusts the machine vision device 3 and the magnetorheological processing module in combination with the maximum polishing wheel position. Step B3 includes the following steps:

[0128] Step B3 includes the following steps:

[0129] B31. Count b data points measured by machine vision device 3 within a second and obtain the time it takes for machine vision device 3 to measure a point. ;

[0130] ;

[0131] B32. Calculate the maximum adjustment amount of the polishing wheel position The time required to control the magnetorheological processing module :

[0132] ;

[0133] in, Indicates the maximum moving speed of robot 1;

[0134] B33, measure the vertical distance between the measuring position of the machine vision device 3 and the working point of the polishing wheel 4 , according to the vertical distance And the time required to calculate the working point of the polishing wheel 4 based on the set number of revolutions per second n of the polishing wheel 4 :

[0135] ;

[0136] in, Indicates the radius of the polishing wheel 4;

[0137] B34. Calculate the maximum speed of robot 1 Minimum moving time between two adjacent processing positions :

[0138] ;

[0139] in, Indicates the distance between two adjacent processing positions;

[0140] B35. Calculation conditions Is it true: If the condition is true, then there is no need to adjust the machine vision device 3 and the polishing wheel 4; if the condition is not true, then it is necessary to adjust the data sampling frequency of the machine vision device 3 and the number of revolutions per second n of the polishing wheel 4 to make the condition true;

[0141] B36, perform mean filtering on the measurement data between each two adjacent processing positions before outputting them, and the number of mean filtered data Needs to be satisfied .

[0142] B4: Combine the third variable range, the maximum polishing wheel position and the maximum ribbon thickness to process the optical element to be processed, and during the processing, the real-time control module adjusts the polishing wheel position in real time. Specifically including:

[0143] Control the polishing wheel to move to the current processing position The current ribbon thickness measured by the machine vision device With the fourth variable range Compare:

[0144] If the current ribbon thickness In the fourth variable range Within, that is , then there is no need to adjust the current polishing wheel position Make adjustments;

[0145] If the current ribbon thickness Not in the fourth variable range Within, that is , you need to check the current polishing wheel position Make adjustments:

[0146] If the current ribbon thickness Greater than or equal to the maximum ribbon thickness ,Right now , the current polishing wheel position Adjust to the maximum polishing wheel position ;

[0147] If the current ribbon thickness Less than the maximum ribbon thickness ,Right now , according to the following formula to calculate the current polishing wheel position Make adjustments:

[0148] .

[0149] All transformation relationships in the above specific embodiments are obtained through fitting. The fitting process includes but is not limited to importing discrete data into Matlab software, using Matlab's polyfit fitting command to complete data fitting, and solving the respective transformation relationships. Polyfit fitting command is a basic general command of Matlab software. This method can more intuitively see the corresponding relationship between correlations and the corresponding function curve.

[0150] It should be understood that the various forms of the processes shown above can be used to reorder, add, or delete steps. For example, the steps described in the present disclosure can be performed in parallel, sequentially, or in a different order, as long as the desired results of the technical solutions disclosed in the present disclosure can be achieved. This is not limited herein.

[0151] The above specific embodiments do not limit the scope of protection of the present invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. A magnetorheological polishing device that adjusts processing posture based on machine vision, characterized by: The device comprises a robot, a control unit, a magnetorheological processing module, and a machine vision device; wherein: the magnetorheological processing module is arranged at the free end of the robot; the robot drives the polishing wheel in the magnetorheological processing module to process the optical element using magnetorheological fluid as the medium, and the machine vision device measures the thickness of the magnetorheological fluid ribbon during the processing; The interior of the control unit includes: a time calculation module for calculating a measurement time of the machine vision device and an adjustment time of the magnetorheological processing module, and adjusting the machine vision device and the magnetorheological processing module according to the measurement time and the adjustment time; a conversion relationship module, which obtains a first conversion relationship according to the thickness of the ribbon and the polishing gap of the polishing wheel, and obtains a second conversion relationship according to the thickness of the ribbon and the polishing wheel position of the polishing wheel; a processing program module, which obtains a processing program according to the removal function obtained by the magnetorheological processing module and imports the processing program into the magnetorheological processing module; A real-time control module adjusts the posture of the robot according to the first conversion relationship, or adjusts the position of the polishing wheel according to the second conversion relationship, so as to maintain the stability of the removal function when processing the optical element.

2. The magnetorheological polishing equipment for adjusting processing posture based on machine vision according to claim 1 is characterized in that: The magnetorheological processing module also includes a transmission belt, a polishing motor, a nozzle, a supply system, a magnet, a real-time adjustment device and a magnetorheological mounting frame; wherein, The magnetorheological mounting frame is arranged on the free end; the polishing wheel and the real-time adjustment device are arranged on the magnetorheological mounting frame, and the real-time adjustment device adjusts the position of the polishing wheel; The polishing motor is arranged on the magnetorheological mounting frame and is connected to the polishing wheel via the transmission belt, so that the polishing motor controls the polishing wheel to rotate, thereby causing the polishing wheel to process the optical element; The nozzle is arranged on the magnetorheological mounting frame along the rotation direction of the polishing wheel, and the supply system delivers magnetorheological fluid to the nozzle; The magnet is arranged on the magnetorheological mounting frame and is close to the working point of the polishing wheel, so that the magnetorheological fluid is affected by the magnetic field strength of the magnet and the rigidity of the magnetorheological fluid is changed.

3. The magnetorheological polishing equipment for adjusting processing posture based on machine vision according to claim 2 is characterized in that: The real-time adjustment device includes a displacement output motor, a lead screw, and a support and fixing frame; wherein, the support and fixing frame is arranged on the magnetorheological mounting frame, the displacement output motor is arranged on the support and fixing frame, and the displacement output motor is connected to the lead screw arranged on the support and fixing frame; the polishing wheel is connected to the nut on the lead screw, so that the lead screw drives the polishing wheel to move; the control unit sends a control signal to the displacement output motor, and when the lead screw of the displacement output motor rotates, the lead screw drives the polishing wheel to move.

4. The magnetorheological polishing equipment for adjusting processing posture based on machine vision according to claim 3 is characterized in that: The machine vision device, the robot and the displacement output motor are respectively connected to the control unit to form respective communication lines, so that the control unit receives and sends signals through the corresponding communication lines.

5. A magnetorheological polishing method based on robot posture control, based on the magnetorheological polishing device with machine vision-based processing posture adjustment according to any one of claims 1 to 4, characterized in that: The following steps are involved: A1: controlling the posture of the robot to drive the polishing wheel to process the test optical element with different polishing gaps, and obtaining the first transformation relationship in the transformation relationship module; A2: setting a first variable range of the polishing gap, and obtaining a second variable range corresponding to the ribbon thickness according to the first conversion relationship; setting a maximum polishing gap, and obtaining a corresponding maximum ribbon thickness according to the first conversion relationship; A3: Controlling the time calculation module to adjust the machine vision device and the magnetorheological processing module in combination with the maximum polishing gap; A4: The optical element to be processed is processed in combination with the second variable range, the maximum polishing gap and the maximum ribbon thickness. During the processing, the real-time control module adjusts the posture of the robot in real time, and uses the change in the polishing gap after the adjustment as input for processing the next processing position, so that the ribbon thickness at the next processing position is within the second variable range.

6. The magnetorheological polishing method based on robot posture control according to claim 5, characterized in that: In step A1, the polishing wheel is controlled to process the test optical element with different polishing gaps, and the ribbon thickness is measured in real time by the machine vision device. The following is obtained in the conversion relationship module: ； in, represents the polishing gap, Indicates the thickness of the ribbon, Indicates the first conversion relationship.

7. The magnetorheological polishing method based on robot posture control according to claim 6, characterized in that: In step A4, the polishing wheel is controlled to move to the current processing position. When the current ribbon thickness is measured by the machine vision device With the second variable range Compare: If the current ribbon thickness In the second variable range If the robot is within the range of , there is no need to adjust the current posture of the robot; If the current ribbon thickness Not in the second variable range If the robot is within the range of , the current posture of the robot needs to be adjusted: If the current ribbon thickness changes Greater than or equal to the maximum ribbon thickness change , represents the initial ribbon thickness, represents the maximum ribbon thickness, and the robot's posture is adjusted according to the following formula: ； in, Indicates the position of the free end at the current processing position; represents the position of the free end at the previous processing position, represents the maximum polishing gap, Indicates the initial polishing gap; If the current ribbon thickness changes Less than the maximum ribbon thickness variation , according to the following formula to calculate the current polishing gap Make adjustments: ； in, Indicates the polishing gap at the current processing position.

8. A magnetorheological polishing method based on polishing wheel position control, based on the magnetorheological polishing device with machine vision-based processing posture adjustment according to any one of claims 1 to 4, characterized in that: The following steps are involved: B1: controlling the polishing wheel to process the test optical element with different polishing gaps, and obtaining the second conversion relationship in the conversion relationship module; B2: setting a third variable range of the polishing wheel position, and obtaining a fourth variable range corresponding to the ribbon thickness according to the second conversion relationship; setting a maximum polishing wheel position, and obtaining the corresponding maximum ribbon thickness according to the second conversion relationship; B3: controlling the time calculation module to adjust the machine vision device and the magnetorheological processing module in combination with the maximum polishing wheel position; B4: The optical element to be processed is processed in combination with the third variable range, the maximum polishing wheel position and the maximum ribbon thickness. During the processing, the real-time control module adjusts the polishing wheel position in real time.

9. The magnetorheological polishing method based on polishing wheel position control according to claim 8, characterized in that: Step B1 includes the following steps: B11: Control the polishing wheel to process the test optical element with different polishing gaps, calculate the removal function volume removal rate at each processing position, and at the same time, the machine vision device measures the ribbon thickness at each processing position in real time, and obtains in the conversion relationship module: ； in, Represents the volume removal rate of the removal function With the thickness of the ribbon The third conversion relationship between B12: Under different polishing gaps, the polishing wheel position is changed individually, and processing is performed on the test optical element to obtain the removal function volume removal rate at each processing position, and then the following is obtained in the conversion relationship module: ； in, Indicates the polishing wheel position The volume removal rate of the removal function The fourth conversion relationship; B13: According to the third conversion relationship and the fourth conversion relationship, the following formula is obtained: ； in, Indicates the second conversion relationship.

10. The magnetorheological polishing method based on polishing wheel position control according to claim 9, characterized in that: In step B4, the polishing wheel is controlled to move to the current processing position When the current ribbon thickness is measured by the machine vision device With the fourth variable range Compare: If the current ribbon thickness In the fourth variable range If the current polishing wheel position is within Make adjustments; If the current ribbon thickness Not within the fourth variable range If the current polishing wheel position is within Make adjustments: If the current ribbon thickness Greater than or equal to the maximum ribbon thickness , the current polishing wheel position Adjust to the maximum polishing wheel position ; If the current ribbon thickness Less than the maximum ribbon thickness , according to the following formula to calculate the current polishing wheel position Make adjustments: 。

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